1. Field of the Invention
This invention relates to composite dosage forms such as pharmaceutical compositions, and components thereof. More particularly, this invention relates to composite dosage forms comprising one or more features that provide anti-counterfeiting characteristics to the dosage forms.
2. Background Information
Dosage forms having two or more distinct portions are useful in the pharmaceutical arts for overcoming a number of commonly encountered challenges, such as, for example, including the separation of incompatible active ingredients, achieving acceptable content uniformity of a low-dose/high potency active ingredient, delivering one or more active ingredients in a pulsatile manner, and providing unique aesthetic characteristics for dosage form identification. Known methods for achieving a multi-portion pharmaceutical dosage form include particle coating, multi-layer tablets, compression-coating, and spray coating techniques. It is also known for example in the household products industry to assemble solid forms from two or more different parts for the purpose of separating active ingredients, or delivering different active ingredients at different times.
One significant opportunity in designing pharmaceutical dosage forms is that of product identification and differentiation. It is useful, both from a consumer safety perspective, and a commercial perspective, to have a pharmaceutical dosage form with a unique appearance that is readily recognizable and identifiable.
One currently used technique for providing unique dosage form identification includes the use of intagliations. Intagliations are impressed marks typically achieved by engraving or impressing a graphical representation, for example a figure, mark, character, symbol such as a letter, a name, a logo, a pictoral representation, and the like, or any combination thereof, in a tablet or other solid dosage form, such as by a punching procedure. U.S. Pat. No. 5,827,535, for example, describes soft gelatin capsules with an external surface having defined thereon an impressed graphical representation. U.S. Pat. No. 5,405,642 discloses a method of highlighting intagliations in white or colored coated tablets by spraying onto said tablets a suspension comprising a filling material having a different color, a waxy material and a solvent, then removing the solvent and the excess filling and waxy material. However, it is often difficult to maintain the waxy material in an amount sufficient to promote suitable bonding of the filling material, yet be suitably removable with solvent.
EP 088,556 relates to a method of highlighting intagliations in white or colored tablets by contacting said tablets with a dry, powdery material having a different color than that of the tablet surface, then removing the excess powdery material not deposited in the intagliations. Disadvantageously, it has been found that the adhesion of the powdery material to the intagliations is not satisfactory as the material shows a tendency to loosen and fall out.
EP 060,023 discloses a method of emphasizing intagliations in colored (i.e. not white) solid articles, in particular tablets, by coating the tablet surface and filling up the intagliations with a coating film comprising an optically anisotropic substance. An optical contrast between the tablet surface and the intagliations is obtained, presumably due to the different orientation of the optically anisotropic substance on the tablet surface and in the intagliations. However, this technique is limited to colored articles and only allows for the use of optically anisotropic filling materials.
Another way to identify and differentiate one dosage form from another is via application of microreliefs to the dosage form. See, e.g., U.S. Pat. No. 4,668,523 and WO 01/10464 (microreliefs in the outer surface of dosage form.) A microrelief is a regular pattern of ridges and grooves and the like that may display a visual effect or optical information when exposed to suitable radiant energy. Disadvantageously, production difficulties could be encountered when using these methods to stamp microrelief patterns into tablets having irregular shapes and/or surfaces.
All of the methods described above for producing a dosage form having one or more separate portions are relatively costly, complex, and time-intensive. Additionally, known methods for producing filled-in intagliations are limited in terms of suitable materials and the obtainable surface configurations and appearance of the resultant dosage form. Besides the above-mentioned limitations on the fill material itself, the tablet subcoating must be non-adhesive enough for the fill-in material to rub off upon tumbling in a hot coating pan. These methods cannot produce filled-in intagliations having the fill material raised above the tablet surface, or even perfectly flush with the tablet surface. The prior art product can only have a fill-in material surface that is slightly depressed, abraded, or concave with respect to the tablet surface.
Another significant challenge in the pharmaceutical industry is the opportunity to minimize manufacturing and packaging costs through standardization. Many drugs are available in several different strength tablets for convenience of dosing different patients with varying needs. Typically, higher strength tablets have greater weight and larger size than tablets having lower amounts of active ingredient. Handling and packaging costs could be reduced by having a dosage form design with the versatility to accommodate multiple different dosage amounts of medication in the same size tablet, yet be readily identifiable to patients and healthcare professionals in terms of identity and strength.
It would be desirable to produce an elegant dosage form having effective identification and distinguishing features using conventional manufacturing and packaging equipment.